Convert local time to gmt time without using TZ Env variable

[Garrett Wollman]

<<On Wed, 11 Apr 2001 23:50:34 +0200, francois reygagne <freygagne at opteway.com> said:

> The right way to do that is to change TZ, but that is not thread-safe

Well, yes and no.  It may be possible to update the timezone code to
use thread-specific data to store its representation of the ``current
timezone''.  I suspect that this would be the easiest (in terms of
code needing to be modified) way to provide a thread-safe timezone
setting.

-GAWollman